Storage subsystem

ABSTRACT

The storage subsystem is connected to an external device and comprises a storage device arrangement portion, on which a plurality of storage devices is arranged, and a control device that controls communications between the plurality of storage devices arranged on the storage device arrangement portion and the external device. The storage device arrangement portion is constituted such that the plurality of storage devices is arranged upright in the directions of two dimensions.

CROSS-REFERENCE TO PRIOR APPLICATION

This application is a Continuation of U.S. patent application Ser. No.12/320,597 filed on Jan. 29, 2009, which is a Reissue application Ser.No. 10/967,361 which issued into U.S. Pat. No. 7,359,186 issued on Apr.15, 2008. Priority is claimed from U.S. patent application Ser. No.12/320,597 filed on Jan. 29, 2009, which claims priority to U.S. Pat.No. 7,359,186 issued on Apr. 15, 2008, which claims the priority ofJapanese Patent Application No. 2004-251940 filed on Aug. 31, 2004, allof which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a storage subsystem that comprises aplurality of storage devices.

BACKGROUND OF THE INVENTION

As a storage subsystem that comprises a plurality of storage devices,the storage subsystem disclosed by Japanese Patent Application Laid OpenNo. 2004-022058, for example, is known. This storage subsystem comprisesa deep enclosure. Storage devices, which are inserted in the depthdirection via the front side, are arranged in the enclosure. In otherwords, the user is able to install a storage device in the storagesubsystem by inserting a storage device in the enclosure in the depthdirection via the front side.

SUMMARY OF THE INVENTION

There is a desire for miniaturization of storage subsystems. Further,small-form factor hard disk drives (so-called 2.5-inch HDD developed forenterprises, for example) have been produced. A method that implementsminiaturization of a storage subsystem by adopting such small-formfactor hard disk drives (abbreviated to ‘SFF-HDD’ hereinafter) as thestorage devices of the storage subsystem has been considered. However,simply changing the installed storage device to an SFF-HDD whileretaining the conventional storage-device installation method isconsidered inadequate from at least one perspective among a variety ofperspectives such as high-density mounting of the storage device, moreefficient cooling of the storage subsystem and maintenance of thestorage subsystem, for example.

Therefore, an object of the present invention is to provide a method ofmounting storage devices that serves at least one of the miniaturizationof the storage subsystem, an increased capacity, and a higherperformance.

Another object of the present invention is to mount a plurality ofstorage devices in a storage subsystem of a high density.

A further object of the present invention is to raise the coolingefficiency of the storage subsystem.

Another object of the present invention is to simplifymaintenance-related manipulation of the storage subsystem and toincrease stability or reliability.

Further objects of the present invention will become evident from thefollowing description.

A storage subsystem according to a first aspect of the present inventionis connected to an external device (Host Computer, for example) andcomprises a storage device arrangement portion on which a plurality ofstorage devices is arranged; and a control device that controlscommunications between the plurality of storage devices arranged on thestorage device arrangement portion and the external device, wherein thestorage device arrangement portion is constituted such that theplurality of storage devices is arranged upright in the directions oftwo dimensions. For example, the storage device arrangement portioncomprises a substrate for the arrangement of storage devices and has amounting portion (Connector, for example) for mounting the plurality ofstorage devices on the substrate.

Further, ‘upright’ storage devices means, for example, that the depthdirection of the storage devices runs in the vertical direction. Inother words, when the storage devices have a first face for which thedepth direction is the normal direction and a second face, for example,a state where the first face is oriented vertically upward and thesecond face is oriented vertically downward is the upright state of thestorage device. Further, in this case, a connector for connecting thestorage device to a substrate or the like may be provided on the firstface or the second face.

In a first embodiment, the storage subsystem further comprises aenclosure for housing the storage device arrangement portion; and anarrangement portion displacement mechanism that displaces the storagedevice arrangement portion inside and outside the enclosure. Thearrangement portion displacement mechanism can displace the storagedevice arrangement portion in the directions of two dimensions (thedepth direction of the enclosure and the reverse direction or thetransverse direction of the enclosure, for example) for example.

In a second embodiment, the storage subsystem according to the firstembodiment is such that the storage device arrangement portion comprisesa first sub-arrangement portion for arranging two or more first storagedevices among the plurality of storage devices; and a secondsub-arrangement portion for arranging two or more second storage devicesamong the plurality of storage devices. The arrangement portiondisplacement mechanism displaces the first sub-arrangement portion andthe second sub-arrangement portion separately.

In a third embodiment, the storage device arrangement portion comprisesa plurality of storage device slots corresponding with a plurality ofstorage devices respectively and is constituted to arrange a pluralityof storage devices, each of which is inserted via the plurality ofstorage device slots. Each of the plurality of storage device slots isconstituted to receive a storage device in an upright state verticallyfrom above.

In a fourth embodiment, the storage subsystem further comprises acooling portion that causes a gas for cooling the storage devicesarranged on the storage device arrangement portion to flow to thestorage device arrangement portion. The storage device arrangementportion is constituted such that a plurality of storage device columnsconsisting of two or more storage devices that follow the direction inwhich the gas flows are formed and the plurality of storage devicecolumns are at equal intervals.

In a fifth embodiment, the plurality of storage devices includes alow-heat storage device that emits heat by consuming first electricalpower and a high-heat storage device that emits heat that is of a highertemperature than the heat of the low-heat storage device by consumingsecond electrical power. The storage subsystem further comprises acooling portion that causes a gas for cooling the storage devicesarranged on the storage device arrangement portion to flow to thestorage device arrangement portion. The storage device arrangementportion is constituted such that the low-heat storage device is disposedupstream in the direction in which the gas flows and the high-heatstorage device is disposed downstream in the direction in which the gasflows. Further, the first and second electrical power may be the same ordifferent.

In a sixth embodiment, the storage subsystem further comprises a coolingportion that causes a gas for cooling the storage devices arranged onthe storage device arrangement portion to flow to the storage devicearrangement portion; and a storage device dummy that is disposed on thestorage device arrangement portion so that the flow of gas is notdisturbed when the maximum number of storage devices that can bearranged is not arranged on the storage device arrangement portion.

In a seventh embodiment, the storage subsystem further comprises acooling portion that causes a gas for cooling the storage devicesarranged on the storage device arrangement portion to flow to thestorage device arrangement portion. The storage device arrangementportion is constituted such that a plurality of storage device columnsconsisting of two or more storage devices that follow the direction inwhich the gas flows are formed and the width of at least one storagedevice column among the plurality of storage device columns is narrowerdownstream than upstream in the direction in which the gas flows.

In an eighth embodiment, the storage device arrangement portion isconstituted such that a plurality of storage device columns consistingof two or more storage devices are formed. The storage subsystem furthercomprises a plurality of operating portions corresponding with theplurality of storage device columns respectively, wherein the operationof an operating portion that is selected by a user from among theplurality of operating portions is detected and the user is allowed toremove a storage device that belongs to the storage device columncorresponding with the selected operating portion.

In a ninth embodiment, the storage subsystem according to the eighthembodiment further comprises a enclosure for housing the storage devicearrangement portion; and an arrangement portion displacement mechanismthat displaces the storage device arrangement portion inside and outsidethe enclosure and in the directions of the two dimensions. The storagedevice column is a column formed in the same direction as thedisplacement direction of the storage device arrangement portion.

In a tenth embodiment, the storage device arrangement portion comprisesa plurality of arrangement positions corresponding with the plurality ofstorage devices respectively. The control device comprises a storageregion that stores control information indicating where in the pluralityof arrangement positions which types of storage devices are arranged andindicating the respective states of each of the storage devices; and acontrol portion that displays a GUI screen. The control portion preparesa plurality of display positions on the GUI screen corresponding withthe plurality of arrangement positions respectively, displays a graphicrepresenting an arranged storage device in each of the plurality ofdisplay positions, and displays at least one of the type and state ofthe storage device corresponding with the graphic on the GUI screen sothat the type and/or state is associated with the graphic.

The storage subsystem according to a second aspect of the presentinvention is a storage subsystem that is connected to an external deviceand that possesses depth, comprising a storage device arrangementportion on which a plurality of storage devices is arranged upright inthe directions of two dimensions that include the depth direction of thestorage subsystem; a control device that controls communications betweenthe plurality of storage devices arranged on the storage devicearrangement portion and the external device; a cooling portion thatcauses a gas for cooling the storage devices arranged on the storagedevice arrangement portion to flow to the storage device arrangementportion; a enclosure for housing the storage device arrangement portion,the control device and the cooling portion; and an arrangement portiondisplacement mechanism that displaces the storage device arrangementportion inside and outside the enclosure and in the directions of thetwo dimensions. The storage device arrangement portion is constitutedsuch that a plurality of storage device columns consisting of two ormore storage devices that follow the direction in which the gas flowsare formed so that the plurality of storage device columns are at equalintervals or so that the width of at least one storage device columnamong the plurality of storage device columns is narrower downstreamthan upstream in the direction in which the gas flows. The storagesubsystem further comprises a plurality of operating portionscorresponding with the plurality of storage device columns respectively,wherein the operation of an operating portion that is selected by a userfrom among the plurality of operating portions is detected and the useris allowed to remove a storage device that belongs to the storage devicecolumn corresponding with the selected operating portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a schematic external view of a storage subsystemaccording to a first embodiment example of an embodiment of the presentinvention;

FIG. 2A shows a three-dimensional outline of the internal constitutionof the basic enclosure 1A;

FIG. 2B is a block diagram that represents the internal constitution ofthe basic enclosure 1A when the basic enclosure 1A is viewed from above;

FIG. 3 provides a schematic view of the constitution of thecross-section 3-3 of the basic enclosure 1A in FIG. 2B;

FIG. 4A provides an enlarged view of the HDD slot 83 in FIG. 2B and ofthe vicinity thereof;

FIG. 4B provides a schematic of a cross section of an HDD 23 that hasbeen inserted completely via the HDD slot 83;

FIG. 5A schematically shows an external view in a case where the HDDgroup installation drawer 19 is withdrawn to a certain extent from thebasic enclosure 1A;

FIG. 5B schematically shows the cross section 5B-5B in FIG. 5A;

FIG. 6A shows the appearance of the flow of an air stream when an HDD 23is mounted in all the HDD mounting portions 31 of the HDD groupinstallation drawer 19;

FIG. 6B is an enlarged view of an intercolumn path in FIG. 6A;

FIG. 7A shows an example of one variation on the cooling design;

FIG. 7B shows an example of another variation on the cooling design;

FIG. 8 shows an example of the constitution within the controller units37A and 37B, an example of the constitution within the switch enclosure3, an example of the constitution within the expansion enclosure 1B, andan example of the constitution of the connection between the controllerunits 37A, 37B and the expansion enclosure 1B;

FIG. 9 shows an example of the constitution of the network in a casewhere the storage subsystem 1 is connected to a communication network;

FIG. 10A shows an example of a GUI screen that is displayed on amanagement terminal 203 when a fault has not occurred;

FIG. 10B shows an example of a GUI screen that is displayed on themanagement terminal 203 when a fault has occurred;

FIG. 11 shows an example of the flow of processing that is executed upuntil a fault is recovered after a fault occurs with an HDD;

FIG. 12A shows a first variation on the integrated withdrawal method;

FIG. 12B shows a second variation on the integrated withdrawal method;

FIG. 12C shows a third variation on the integrated withdrawal method;

FIG. 13A provides an outline of one variation on the separate withdrawalmethod;

FIG. 13B serves to illustrate the variation in detail;

FIG. 14A shows a first variation on the removal method for the HDD 23;

FIG. 14B shows a second variation on the removal method for the HDD 23;

FIG. 15A shows a first variation on the cooling design for increasingthe velocity of the cooling air stream on the rear side;

FIG. 15B shows a second variation on the cooling design for increasingthe velocity of the cooling air stream on the rear side;

FIG. 16 shows one variation on the constitution within the expansionenclosure 1B;

FIG. 17 shows another variation on the constitution in the expansionenclosure 1B;

FIG. 18 shows yet another variation on the constitution within theexpansion enclosure 1B and one variation on the constitution of theconnection between the controller units 37A, 37B and each HDD 23;

FIG. 19 shows the constitution of the HDD group installation drawer inthe expansion enclosure 1B in detail; and

FIG. 20 shows an example in which the columns constituted by theSATA-HDD 23A and the columns constituted by the SAS-HDD 23S are arrangedalternately.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A storage subsystem relating to an embodiment of the present inventionwill be described hereinbelow with reference to the drawings. A varietyof storage devices, such as hard disk drives (abbreviated to ‘HDD’hereinafter), DVD (Digital Versatile Disks) drives or magnetic tapedrives, for example, can be adopted as the storage devices that areinstalled in the storage subsystem. The storage devices are referred toas ‘HDD’ hereinbelow.

First Embodiment Example

FIG. 1 provides a schematic external view of a storage subsystemaccording to a first embodiment example of an embodiment of the presentinvention.

A storage subsystem 1 is a RAID (Redundant Array of Inexpensive Disks)system, for example. The storage subsystem 1 comprises a basic enclosure1A, a plurality of (or a single) expansion enclosures 1B, 1B, . . . ,and a switch enclosure (abbreviated to ‘SW enclosure’ hereinafter) 3that electrically connects the basic enclosure 1A and expansionenclosures 1B.

The SW enclosure 3 comprises a switch device (not shown). An HDDconnection portion (not shown) within the expansion enclosure 1B, whichwill be described subsequently, is connected to the switch device via acable 15. Further, controller units (not shown) in the basic enclosure1A (described subsequently) are connected to the switch device viacables 13. As a result, the controller units are able to access the HDDsin the expansion enclosure 1B via the switch device and the HDDconnection portion within the expansion enclosure 1B.

The expansion enclosure 1B comprises, on the front side thereof, an HDDgroup housing space 9 for housing an HDD group comprising a plurality ofHDD and comprises, on the rear side thereof, an HDD connection portionhousing space 11 for housing an HDD connection portion. The HDDconnection portion is connected to the switch device within the SWenclosure 3 via the cable 15.

The basic enclosure 1A comprises, on the front side thereof, an HDDgroup housing space 5 for housing an HDD group and comprises, on therear side thereof, a controller housing space 7 for housing a controllerunit, fan unit (not shown), and so forth of the storage subsystem 1. Thecontroller unit is connected electrically to the HDD in the HDD grouphousing space 5 and is connected electrically to the switch device inthe SW enclosure 3 via a cable 13. Accordingly, the controller unit isable to access the HDD in the HDD group housing space 5 and is able toaccess the HDD in the expansion enclosure 1B via the switch device inthe SW enclosure 3 and the HDD connection portion within the expansionenclosure 1B.

Further, the SW enclosure 3 may be left out of the storage subsystem 1.In this case, the controller unit in the basic enclosure 1A may beconnected to the HDD connection portion in the expansion enclosure 1Bvia a cable. Further, an HDD 23 may be of any size (a 3.5-inch HDD or2.5-inch HDD is acceptable, for example).

Further, in the storage subsystem 1, the switch device (not shown) inthe SW enclosure 3 may be installed in a enclosure 3 separate from thebasic enclosure 1A or expansion enclosure 1B, as mentioned earlier, ormay be installed in the basic enclosure 1A or expansion enclosure 1B. Inthe former case, the expansion capability is high and, in the lattercase, miniaturization of the storage subsystem 1 is feasible becausesame is complete even if the SW enclosure 3 is not provided.

FIG. 2A shows a three-dimensional outline of the internal constitutionof the basic enclosure 1A. FIG. 2B is a block diagram that representsthe internal constitution of the basic enclosure 1A when the basicenclosure 1A is viewed from above. FIG. 3 provides a schematic view ofthe constitution of the cross-section 3-3 of the basic enclosure 1A inFIG. 2B.

The basic enclosure 1A is a rectangular parallelepiped with an internalspace and has depth from the front side toward the rear side. Theinternal space of the basic enclosure 1A is divided into the HDD grouphousing space 5 and the controller housing space 7. A back plane 17 isprovided between the HDD group housing space 5 and the controllerhousing space 7 and the HDD group housing space 5 and controller housingspace 7 are partitioned by the back plane 17.

An HDD group installation drawer 19 for installing an HDD group isprovided within the HDD group housing space 5. A drawer slide mechanism27 that enables the HDD group installation drawer 19 to slide in thedepth direction and in the reverse direction (that is, in bothdirections toward the rear side and front side) is provided in the basicenclosure 1A. The drawer slide mechanism 27 may be any mechanism as longas same allows the HDD group installation drawer 19 to slide. As oneexample, the drawer slide mechanism 27 comprises a rail 25 on which theHDD group installation drawer 19 is placed, and a plurality of guiderollers 29 that guide the rail 25 in both directions toward the frontand rear sides of the basic enclosure 1A, as shown in FIG. 3. Theplurality of guide rollers 29 stand in a line in the depth direction.The provision of such a drawer slide mechanism 27 makes it possible tosuppress vibrations of the HDD 23 and thus prevent problems such assystem stoppage from occurring. Further, a stopper for limiting thedistance over which the HDD group installation drawer 19 is withdrawnmay be provided in the basic enclosure 1A. The front face of the basicenclosure 1A may be a door that can be opened and closed that may beopen beforehand. As a result, the HDD group installation drawer 19 canbe inserted and withdrawn.

The HDD group installation drawer 19 is arectangular-parallelepiped-shaped box with depth, for example (any shapeis permissible as long as the shape has depth). A plurality of HDD 23 isarranged in the HDD group installation drawer 19 in the directions oftwo dimensions. More specifically, two or more HDDs 23 are arranged fromthe front side toward the rear side (that is, in the depth direction) inthe HDD group installation drawer 19, for example. Here, the depthdirection of the HDD 23 is orthogonal to the depth direction of thebasic enclosure 1A and is parallel to the height direction of the basicenclosure 1A. To state this another way, two or more HDDs 23 arearranged in a standing state in the depth direction of the basicenclosure 1A within the HDD group installation drawer 19. In otherwords, each HDD 23 is a rectangular parallelepiped the verticaldimension of which is the longest, the horizontal dimension of which isthe second-longest, and the height of which is the third-longest. Therespective HDDs 23 are arranged such that the vertical of the HDD 23 isparallel to the height of the basic enclosure 1A and the horizontal ofthe HDD 23 is parallel to the depth of the basic enclosure 1A.Accordingly, the HDD 23 can be provided at a high density within a fixedspace. According to the present embodiment, two or more (four, forexample) HDDs 23 are arranged in the depth direction in the HDD groupinstallation drawer 19 and two or more (twenty-two, for example) HDDs 23are arranged in the width direction, for example. Further, in thisembodiment, the HDDs 23 may be arranged such that the width of the HDDs23 follows the depth direction of the basic enclosure 1A, but mayinstead be arranged such that the height of the HDD 23 follows the depthdirection of the basic enclosure 1A. Hereinbelow, an arrangement of twoor more HDDs 23 in the depth direction of the basic enclosure 1A (thatis, in the vertical width direction of the basic enclosure 1A issometimes referred to as a ‘column’ or ‘HDD column’ and an arrangementof two or more HDDs 23 in the transverse width direction) is sometimesreferred to as a ‘row’ or ‘HDD row’. An HDD column may be parallel tothe depth direction or inclined with respect to the depth direction.Likewise, an HDD row may be parallel to the transverse width directionor inclined with respect to the depth direction. Furthermore, thedistance between an HDD column and an adjacent HDD column may be thesame between all the columns or may be different. Likewise, the distancebetween an HDD row and an adjacent HDD row may be the same between allthe rows or may be different.

An HDD group mounting substrate 21 is laid on the bottom of the HDDgroup installation drawer 19. The HDD group mounting substrate 21 is aprinted substrate on which a wiring pattern has been printed, forexample. A plurality of HDD mounting portions 31 (connectors that areembedded in the substrate 21, for example), to which connectors 32 ofthe HDD 23 (or connectors of canisters in which the HDD 23 areinstalled) are physically connected, are provided densely over the wholearea of the HDD group mounting substrate 21. Stated using the example inFIGS. 2A, 2B, and 3, two or more (four, for example) HDD mountingportions 31 are arranged in the row direction (width direction) on theHDD group mounting substrate 21 and two or more (twenty-two, forexample) HDD mounting portions 31 are arranged in the column direction(depth direction). Further, a plurality of HDDs 23 mounted in the HDDgroup installation drawer 19 may be constituted by only HDDs of one type(HDDs of the same standard, for example), or may be constituted by HDDsof a plurality of types. In this first embodiment example, two types aremixed, namely SATA (Serial ATA)-standard HDDs (‘SATA-HDDs’ hereinafter)and SAS (Serial Attached SCSI)—standard HDDs (‘SAS-HDDs’ hereinafter).

As shown in FIGS. 2B and 3, a plurality of HDD slots 83 arranged in thedirections of two dimensions (in the row and column directions, forexample) is provided on the upper face of the HDD group installationdrawer 19. HDDs 23 are inserted in the HDD slots 83. The HDD 23 has afront face and rear face, the depth direction of the HDD 23 being thenormal direction, and has a connector 32 on the rear face, for example.When the HDD 23 is completely inserted in the HDD 83 with the rear faceof the HDD 23 oriented vertically downward, the connector 32, which isprovided on the rear face of the HDD 23, is physically connected to theHDD mounting portion 31 in the HDD group mounting substrate 21. Further,a door, which is in a closed state when the HDD 23 is pressed into theopening of the HDD slot 83 to open same and there is no HDD 23 and/orwhen the HDD 23 is inserted completely, for example, may be provided.The provision of such a door makes it possible to prevent dust and soforth from entering via the HDD slot 83.

One or more (two, for example) first state display lamps (LED, forexample) 81A and 81B and an eject button 85 are provided close to eachHDD slot 83 (near the front side of the opening of the HDD slot 83, forexample) in the upper face of the HDD group installation drawer 19. FIG.4A provides an enlarged view of the HDD slot 83 in FIG. 2B and of thevicinity thereof, while FIG. 4B provides a schematic of a cross sectionof an HDD 23 that has been inserted completely via the HDD slot 83. Theleft-hand figure in FIG. 4B shows an eject mechanism 86 and HDD 23 asviewed from the side of the basic enclosure 1A and the right-hand figurein FIG. 4B shows the eject mechanism 86 and HDD 23 as viewed from thefront face of the basic enclosure 1A. Controller units 37A and 37B,which will be described subsequently, are able to ignite and turn off atleast one of the first-state display lamps 81A and 81B that correspondwith the HDD slot 83 comprising the HDD 23 in accordance with the stateof a certain HDD 23 (access in progress, for example), for example. Whenthe eject button 85 is operated, the HDD 23 in the HDD slot 83corresponding with the eject button 85 is extracted via the HDD slot 83by means of the eject mechanism 86. Further, the extraction of the HDD23 may be performed by means of computer processing of the controllerunits 37A and 37B when a signal indicating that the eject button 85 hasbeen pressed is sent to the controller units 37A and 37B, for example,or may be executed by means of a mechanical constitution not requiringcomputer processing. Further, removal of the HDD 23 is not limited to amethod that adopts the eject mechanism 86. Several variations may beconsidered. These variations will be described in the third embodimentexample (described subsequently).

As shown in FIG. 3, a lock mechanism 87 is provided for each HDD slot83. The lock mechanism 87 is a mechanism that controls the insertion ofthe HDD 23 into the corresponding HDD slot 83 and/or the removal of theHDD 23 from the HDD slot 83. When the lock mechanism 87 has locked theHDD slot 83, removal of the HDD 23 via the HDD slot 83 is not possibleand, when the lock is released, removal of the HDD 23 via the HDD slot83 is permitted. A variety of methods can be adopted as the method oflocking the HDD slot 83.

The HDD group installation drawer 19 has a second state display lamp 33and a lock control button 35 provided for each column as shown in FIG.2A. The second state display lamp (LED, for example) 33 and lock controlbutton 35 are electrically connected to the controller unit 37A (and/or37B) via the HDD group mounting substrate 21, for example. In a casewhere the occurrence of an anomaly is detected with at least one of thetwo or more HDDs 23 belonging to a certain column, the controller unit37A ignites the second state display lamp 33 that corresponds with thiscolumn. Further, upon detecting that the lock control button 35corresponding with a certain column has been operated, the controllerunit 37A enables the mounting and/or removal of the HDD 23 belonging tothe column and prohibits the mounting and/or removal of the HDD 23belonging to each of the other columns. To describe this morespecifically, upon detecting that the lock control button 35corresponding with a certain column has been operated, the controllerunit 37A controls each lock mechanism 87 corresponding with the HDDslots 83 belonging to the column to enable removal (or mounting) of theHDDs 23 belonging to the column and controls each lock mechanism 87corresponding with the HDD slots 83 belonging to each of the othercolumns to prohibit removal (or mounting) of the HDDs 23 via the HDDslots 83 belonging to each of the other columns, for example. As aresult, unless the lock control button 35 corresponding with the desiredcolumn is pressed, the HDDs 23 cannot be removed via the HDD slots 83belonging to the column. Hence, the unintentional removal of HDDs 23 bymistake can be prevented.

A connector (referred to as a ‘back plane front-face connector’hereinbelow) 47 that is connected to the front face of the back plane 17is provided on the rear side of the HDD group installation drawer 19.The back plane front-face connector 47 is electrically connected to theHDD group mounting substrate 21 (may be physically connected).

In the middle area of the controller housing space 7, multiplexed(duplexed, for example) controller units 37A and 37B and a power supplyunit 39, which constitutes a secondary power supply for the controllerunits 37A, 37B and the HDDs 23 in the basic enclosure 1A, is provided.The controller units 37A and 37B and the power supply unit 39 arearranged in a stacked configuration. For example, the power supply unit39 is located in the upper layer and the controller units 37A and 37Bare located in a layer below the battery 39. A connector is provided onthe front and rear sides of each of the controller units 37A, 37B andpower supply unit 39. A front-side connector 41 is physically connected(or electrically connected) to the rear side 17B of the back plane 17and a rear-side connector 43 is physically or electrically connected toa variety of targets (communication network, back plane 17, the switchdevice in the SW enclosure 3 or mains power supply, for example). As aresult, the power supply unit 39 can supply electrical power to each ofthe HDDs 23, each of the controller units 37A and 37B, and/or each offans 45A, 45B (described subsequently) via the back plane 17. Further,one controller unit 37A (or 37B) is able to access the other controllerunit 37B (or 37A) via the front-side connector 41 and back plane 17.Furthermore, the controllers 37A and 37B are able to access an optionalHDD 23 via the rear-side connector 43 (or front-side connector 41), theback plane 17 and the HDD group mounting substrate 21 and are able toaccess an HDD in the expansion enclosure 1B via the SW enclosure 3. Thecontroller units 37A and 37B are also able to receive a read command orwrite command from a host device via the rear-side connector 43 and thenaccess an optional HDD 23 via the back plane 17 in response to this readcommand or write command. The controller units 37A and 37B may alsoexecute specified fault processing when a maintenance/replacement modeis executed (when it is detected that the lock control buttoncorresponding with a certain column has been pressed, for example). Aspecific example will be provided below. For example, a vibration sensor71, which outputs a signal with a value corresponding to the vibrationof the HDD group installation drawer 19 to the controller units 37A and37B, is provided on the HDD group mounting substrate 21. The controllerunits 37A and 37B are provided with a vibration threshold value storagearea 73 (provided in the memory of the controller circuit (mentionedsubsequently) in the controller unit 37A, for example) for storing athreshold value for the signal value from the vibration sensor 71(‘vibration threshold value’ hereinafter). The vibration threshold valueis set at a value that is sufficiently higher than the signal valueoutputted in accordance with the vibration that occurs when the HDDgroup installation drawer 19 is withdrawn or inserted. The controllerunits 37A and 37B compare the value of the signal received from thevibration sensor 71 with the vibration threshold value that is stored inthe vibration threshold value storage area 73. When the value of thereceived signal is lower than the vibration threshold value, thecontroller units 37A and 37B judge that the HDD group installationdrawer 19 has been withdrawn or pushed in and the specified faultprocessing corresponding with this judgment result is executed. When thevalue of the received signal is higher than the vibration thresholdvalue, the controller units 37A and 37B judge that an error has occurredand normal fault processing is executed. Where normal fault processingis concerned, the controller units 37A and 37B execute processing tomove data in each HDD 23 to an HDD 23 in another enclosure (theexpansion enclosure 1B, for example), for example. On the other hand,where specified fault processing is concerned, the controller units 37Aand 37B access an optional HDD 23 in response to a write command or readcommand from a host device and, when this access fails, the controllerunits 37A and 37B execute a higher number of retries than the normalnumber (that is, the number of times a retry is executed is then greaterthan the normal number).

Fan units 45A and 45B are provided to the left and right of the middlearea of the controller housing space 7. The fan units 45A and 45B areduplexed fan units. The fan units 45A and 45B comprise a connector onboth the front and rear sides. A front-side connector 51 is connectedphysically or electrically to the rear face 17B of the back plane 17. Asa result, the fan units 45A and 45B can be driven as a result ofreceiving a supply of electrical power via a rear-side connector 53 andthis driving allows air to be introduced from the front face of thebasic enclosure 1A via the HDD group installation drawer 19, forexample. As a result, the interior of the HDD group installation drawer19 is cooled.

The back plane 17 is a printed substrate printed with a wiring patternthat has a front face 17S and a rear face 17B. A connector 48 to whichthe connector 47 of the HDD group installation drawer 19 is physicallyor electrically connected is provided on the front face 17S of the backplane 17. A connector 55, to which the connectors 41 of the power supplyunit 39 and controller units 37A and 37B are physically or electricallyconnected, and a connector 57, to which the connectors 51 of the fanunits 45A and 45B are physically or electrically connected, are providedon the rear face 17B of the back plane 17. The connectors 48, 55, and57, which are provided on the back plane 17, are embedded in the backplane 17, for example. Because the HDD group installation drawer 19, inwhich the HDDs 23 are mounted, the controller units 37A and 37B, and soforth, are connected to the back plane 17, the controller units 37A and37B are able to access an optional HDD 23 via the back plane 17 and HDDgroup mounting substrate 21. Further, as will be described subsequently,the back plane 17 has a hole 61 for transmitting air, which has beenintroduced from the front face of the basic enclosure 1A and that haspassed within the HDD group installation drawer 19, to the rear side. Asshown in FIG. 3, the insertion and extraction direction of the HDD 23 inthe HDD group installation drawer 19 is a direction that transects (isorthogonal to, for example) the direction of air flow (indicated by thedotted line). The HDD mounting portions 31 are arranged in the directionof air flow and not opposing the direction of air flow. As a result, itis possible to prevent dust from falling onto the HDD group mountingsubstrate 21 and hence the occurrence of contact problems between theHDD group mounting substrate 21 and HDD 23, and so forth.

An outline of the constitution and functions of the basic enclosure 1Awas provided above. The constitution in the HDD group housing space 5can also be applied to the HDD group housing space 9 of the expansionenclosure 1B.

Furthermore, a description will be provided below for the installationand removal of the HDD 23 in and from the HDD group installation drawer19 when the HDD group installation drawer 19 of the basic enclosure 1Ais withdrawn or pushed in.

FIG. 5A schematically shows an external view in a case where the HDDgroup installation drawer 19 is withdrawn to a certain extent from thebasic enclosure 1A. FIG. 5B schematically shows the cross section 5B-5Bin FIG. 5A. Further, the cross-sectional view shown in FIG. 5B is a moreschematic view than that of FIG. 3.

The HDD group installation drawer 19 can be withdrawn smoothly towardthe front side (in a direction that is the reverse of the depthdirection of the basic enclosure 1A) and can be pushed in the depthdirection by means of the drawer slide mechanism 27 mentioned earlier.In a case where an optional HDD 23 is mounted, the user withdraws theHDD group installation drawer 19 and inserts the HDD 23 downwardvertically from above into an optional HDD slot 83 among a plurality ofHDD slots 83. The user also withdraws the HDD group installation drawer19 and removes the HDD 23 in the optional HDD slot 83 upward verticallyfrom below when an optional HDD 23 is removed from the basic enclosure1A. Such installation or removal of the HDD 23 can be performed evenwhen the power supply of the controller units 37A, 37B, HDD 23, and soforth is ON. That is, hot swapping of the HDD 23 is possible.

As shown in FIGS. 5A and 5B, the HDD group installation drawer 19 iswithdrawn separately from the back plane 17. In other words, the rearside parts (the back plane 17 and the parts that are further in thedepth direction than the back plane 17) are fixed. Only the HDD groupinstallation drawer 19 slides. A cable 63, which provides an electricalconnection between the connector 47 of the HDD group installation drawer19 and the front-side connector 48 of the back plane 17, is provided.The cable 63 is a flexible-film-like cable, for example. As a result, ina state where the HDD group installation drawer 19 is completely housedin the basic enclosure 1A, for example, the cable 63 is housed in thespace between the HDD group installation drawer 19 and the bottom of thebasic enclosure 1A (a space with the height of the rail 25, forexample). Further, it is considered advantageous from the point of viewof reducing the number of parts and to make is easy to exchange the rearparts if, as shown in FIGS. 5A and 5B, the whole of the HDD groupinstallation drawer 19 slides and the rear parts are fixed. Further, anextendable rail 25 may be provided in place of the cable 63 in aconstitution in which only the HDD group installation drawer 19 iswithdrawn. In such a case, when the HDD group installation drawer 19 iswithdrawn, the rail 25 extends (that is, grows longer) in a directionthat is the reverse of the depth direction and contracts (that is, growsshorter) in the depth direction when the HDD group installation drawer19 is pushed in.

The method of withdrawing the HDD group installation drawer 19 is notlimited to the method shown in FIGS. 5A and 5B. A variety of variationsmay be considered. A variety of variations will be described in thesecond embodiment example (described subsequently).

Further, in the first embodiment, as mentioned earlier, a plurality ofHDDs 23 is arranged in the directions of two dimensions in the HDD groupinstallation drawer 19 and this plurality of HDDs 23 is arranged atequal intervals in the row direction (that is, in a direction that isorthogonal to the depth direction and not in a vertical direction). As aresult, it is possible to make uniform the air stream flowing throughthe long space (referred to as an ‘intercolumn path’ hereinafter) in thedepth direction that arises between one column and an adjacent column.Further, this fact is described in detail below.

FIG. 6A shows the appearance of the flow of an air stream when an HDD 23is mounted in all the HDD mounting portions 31 of the HDD groupinstallation drawer 19. FIG. 6B is an enlarged view of an intercolumnpath in FIG. 6A.

When an HDD 23 is mounted in all the HDD mounting portions 31 of the HDDgroup installation drawer 19, the widths of all of the intercolumn paths91 are the same length. Further, the width of the respective intercolumnpaths (that is, the paths for the air stream that flows from the frontside to the rear side) 91 is constant from the end of the front side(front end) to the end of the rear side (rear end). Hence, the volumeand velocity of the air stream flowing through the intercolumn paths 91is the same for all the intercolumn paths 91. Hence, the cooling designis straightforward. For example, an air stream flowing through anintercolumn path 91 is hotter on the rear-end side of the intercolumnpath 91 than on the front-end side thereof due to the heat generated bythe HDD 23. The cooling design can be executed based on that fact.

FIG. 7A shows an example of one variation on the cooling design.

For example, a SAS-HDD reaches a high temperature more readily than aSATA-HDD (in other words, readily emits more heat). This is thought tobe because the number of rotations per unit of time is higher for aSAS-HDD than for a SATA-HDD, for example. For this reason, when aSAS-HDD is disposed on the front side of the basic enclosure 1A and aSATA-HDD is disposed further toward the rear side, the SATA-HDD disposedon the rear side receives hot air. As a result, the cooling efficiencyof a SATA-HDD is poor.

Therefore, as shown in FIG. 7A, SATA-HDDs (SATA-HDDs arranged in the rowdirection, for example) are mounted on the front side of the HDD groupinstallation drawer 19 (that is, on the upstream-side in the air flowdirection) and SAS-HDDs (SAS-HDDs arranged in the row direction, forexample) are mounted on the rear side of the HDD group installationdrawer 19 (that is, on the downstream side in the air flow direction).More specifically, SATA-HDDs are mounted throughout the one or more rowson the front side, and SAS-HDDs are mounted throughout the one or morerows on the rear side, as shown in FIG. 7A, for example. As a result,the SATA-HDDs receive an air stream at a lower temperature than when theSAS-HDDs are disposed closer to the front side than the SATA-HDDs (morespecifically, an air stream that has not been deprived of the heat ofany HDD or that has the heat taken from the SATA-HDDs that are at alower temperature than the SAS-HDDs). Hence, in comparison with a casewhere the SAS-HDDs are disposed closer to the front side than theSATA-HDDs, the cooling efficiency of the SATA-HDDs can be raised.Further, the air stream received by the SAS-HDDs is at a highertemperature than in a case where the SAS-HDDs are disposed closer to thefront side than the SATA-HDDs. However, because the air stream is at alower temperature than the temperature of the SAS-HDD, cooling of theSAS-HDDs can also be performed. That is, in comparison with a case wherethe SAS-HDDs are disposed closer to the front side than the SATA-HDDs,the overall cooling efficiency can be increased.

FIG. 7B shows an example of another variation on the cooling design.

In a case where HDDs 23 are mounted on all the HDD mounting portions 31of the HDD group installation drawer 19, the widths of all theintercolumn paths 91 are the same length as mentioned earlier.Consequently, the volume and velocity of the air stream flowing throughthe intercolumn paths 91 is also the same for the other intercolumnpaths 91. However, HDD 23 may not be installed in all the HDD mountingportions 31. In this case, the width at a certain point of a certainintercolumn path 91 differs from the width at other points. Hence, thepossibility that the cooling efficiency will drop exists.

Therefore, as shown in FIG. 7B, a dummy HDD 94 is inserted in a vacantHDD slot 83F in which an HDD 23 has not been inserted. Here, the dummyHDD 94 may be any dummy as long as same is a solid body with the samevolume and shape as the HDD 23. For example, the dummy HDD 94 may be adifferent box with the same volume and shape as the HDD 23.

Therefore, because the width at any point of the intercolumn path 91 isrendered the same by inserting the dummy HDDs 94 in vacant HDD slots83F, a drop in cooling efficiency can be prevented.

Further, the dummy HDDs 94 may be located anywhere as long as same areinserted in vacant HDD slots 83F. For example, dummy HDDs 94 may bedistributed equally throughout the HDD group installation drawer 19 ormay be arranged concentrated in a certain location. More specifically,for example, HDDs (SATA-HDDs, for example) may be arranged in the firstrow closest to the front face (the row closest to the air streamopening), HDDs (SAS-HDDs, for example) may be arranged in the mth row(m=4, for example) that is furthest from the front face, and dummy HDDs94 may be installed throughout at least one row between the first andmth rows.

Further, when an HDD is removed from a certain row and a first vacantHDD slot 83F becomes available, a second vacant HDD slot 83F may beprepared by removing an HDD from an HDD slot 83 in another row and theninserting the HDD thus removed into the first vacant HDD slot 83F, forexample. A dummy HDD 94 may be inserted into the second vacant HDD slot83F thus prepared to replace the HDD 23. That is, the dispositionalrelationship between the HDD 23 and the dummy HDD 94 can be chosen bythe user.

Further, as mentioned earlier, a door, which is in a closed state whenthe HDD 23 is pressed into the opening of the HDD slot 83 to open sameand there is no HDD 23 and/or when the HDD 23 is inserted completely,for example, may be provided. In other words, a shutter, which preventsthe opening of the HDD slot 83F from being opened when an HDD 23 is notinserted may be provided at the opening of the HDD slot 83.

Further, the state display lamps 81A and 81B corresponding with each ofthe HDD slots 83 (see FIGS. 2B and 4A) execute a display thatcorresponds with a case where a dummy HDD 94 has been inserted into theHDD slots 83 (that is, the user is notified that the dummy HDD 94 hasbeen inserted). Hard control can also be implemented by means ofcomputer control by the controller units 37A and 37B. For example, theface opposite the HDD group mounting substrate 21 of the dummy HDD 94comprises a projection of a certain length and the HDD group mountingsubstrate 21 comprises a contact point for detecting contact with theprojection. When the dummy HDD 94 is inserted and the projection makescontact with the contact point, the state display lamps 81A and 81B mayexecute a corresponding display (the flicker of a green lamp, forexample).

In addition, the state display lamps 81A and 81B corresponding with eachHDD slot 83 may execute a display that corresponds with a status otherthan a status that indicates that the dummy HDD 94 has been inserted.For example, when the HDD 23 is inserted and an error is not detectedwith the HDD 23, the controller units 37A and 37B may cause the statedisplay lamps 81A and 81B corresponding with the HDD slot 83 into whichthe HDD 23 has been inserted to execute a display (a red lamp lights up,for example) that represents an active status. Further, in a case wherethe HDD 23 has been inserted and an error with the HDD 23 is detected,for example, the controller units 37A and 37B may cause the statedisplay lamps 81A and 81B corresponding with the HDD slot 83 into whichthe HDD 23 has been inserted to execute a display indicating a fault(green lamp is goes out, for example). Further, upon detecting that thelock control button 35 has been pressed, the controller units 37A and37B may render the display of the state display lamps 81A and 81B of thecolumn corresponding with the lock control button 35 an aspect thatcorresponds with such detection (a green lamp and red lamp may light upalternately, for example). As a result, the user learns that an HDD 23has been removed from an HDD slot 83 belonging to any column and hencethe erroneous removal of an HDD 23 that is not intended by the user canbe prevented. Further, when it is detected that the eject button 85 of acertain HDD slot 83 belonging to a column corresponding with the lockcontrol button 35 has been pressed, the controller units 37A and 37B maycause the state display lamps 81A and 81B corresponding with the certainHDD slot 83 to execute a display (flicker of a green lamp, for example)that signifies that removal of the HDD 23 is allowed.

Variations in the cooling design were described above. However, thedetails of the cooling design are not limited to the examples above.Rather, a variety of other variations may be considered. Such avariation will be described by means of a subsequent fourth embodimentexample.

FIG. 8 shows an example of the constitution within the controller units37A and 37B, an example of the constitution within the switch enclosure3, an example of the constitution within the expansion enclosure 1B, andan example of the constitution of the connection between the controllerunits 37A, 37B and the expansion enclosure 1B.

The controller units 37A and 37B are provided with controller circuits101A and 101B respectively. Because the constitution of the controllercircuits 101A and 101B is the same, when this is described taking thecontroller circuit 101A as a representative example, the controllercircuit 101A comprises a CPU 105, a bridge circuit (abbreviated to‘Bridge’ in FIG. 8) 107, a Fibre Channel Interface circuit (abbreviatedto ‘IF-FC’ in FIG. 8) 111, a cache memory (abbreviated to ‘Cache’ inFIG. 8) 114, a data transfer control circuit (abbreviated to ‘D_CTL’) inFIG. 8) 113, a SAS interface circuit (abbreviated to ‘IF-SAS’ in FIG. 8)115, a fanout expander (abbreviated to ‘F-Exp’ in FIG. 8) 116, and amain memory (abbreviated to simply ‘memory’ in FIG. 8) 109. The CPU 105performs centralized control of the controller circuit 101A (control ofeach element of the controller circuit, for example). The bridge circuit107 controls the connection between each of the elements of thecontroller circuit that are connected to the Bridge 107 (CPU 105, mainmemory 109, and so forth) and the elements of another controller circuitthat are connected to the Bridge 107. The IF-FC 111 is a circuit inwhich a chip for processing the FC (Fibre Channel) protocol is installedand to which a host device (not shown) is connected via a SAN (StorageArea Network), for example. The Cache 114 is a memory for the temporarystorage of data that is written to the HDD 23, data that is read fromthe HDD 23, and so forth. The IF-FC 111, cache memory (abbreviated to‘Cache’ in FIG. 8) 114, and D_CTL 113 control data transfers betweeneach of the elements of the controller circuit that are connected to theD_CTL 113 and the elements of another controller circuit that areconnected to the D_CTL 113. The IF-SAS 115 is a circuit in which a chipthat processes the SAS protocol is installed and which communicates witha SAS-HDD 23S via an F-Exp 116. The F-Exp 116 is one type of switchcircuit that comprises j (j is an integer of one or more) first portsthat are connected to the IF-SAS 115 and k (k>j) second ports that areconnected to a plurality of rear-side connectors 43 of the controllerunit 37A. The memory 109 may be a ROM for storing a computer programthat is read to the CPU 105 or may be RAM that comprises a work regionfor the CPU 105. The front-side connector 41 may be connected to theBridge 107 and may be connected to the front-side connector 41 of thecontroller unit 37B via a path 106. As a result, the controller circuit101A is able to access the other controller circuit 101B. For example,the controller circuit 101A may write data read from the HDD 23 to theCache 114 and may write data to the Cache in the controller circuit 101Bvia the path 106.

One or more (two, for example) switch devices 118 may be provided in theswitch enclosure 3. Each of the switch devices 118 may be provided witha plurality of edge expanders (abbreviated to ‘E-Exp’ in FIG. 8) 117.The E-Exp 117 is one kind of switch circuit that comprises p (p is aninteger of one or more) first ports that are connected to the controllerunit 37A or 37B and q (q>p) second ports that are connected to one ormore expansion enclosures 1B.

The expansion enclosure 1B comprises a disk connection portion 120, aplurality of HDD 23, and a back plane (abbreviated to ‘BP’ hereinafter)121 that connects the disk connection portion 120 and the plurality ofHDD 23.

A switch portion 119 in the expansion enclosure of the disk connectionportion 120 implements the same processing as the switch portion 118.

A BP 121 has a first port 126, which is connected to the switch portion119 in the expansion enclosure, and a second port 128, which isconnected to the HDD 23. A second port set 128 of the BP 121 has twosecond ports (not shown) and, connected to these two second ports viathe switch device 118 and switch portion 119 in the expansion enclosureare the two controller circuits 101A and 101B respectively. In caseswhere the HDDs 23 connected to the two second ports are SAS-HDD 23S, theSAS-HDDs 23S have two connectors 32. Hence, the SAS-HDDs 23S areconnected directly to the two second ports (to one second port set 128).On the other hand, in cases where the HDDs 23 connected to the twosecond ports are SATA-HDDs 23A, the SATA-HDDs 23A have one connector 32,and hence the SATA-HDDs 23A are connected via a path switch (abbreviatedto ‘PS’ hereinafter) 123 to two second ports (to one second port set128). The PS 123 is a device (a chip, for example) that comprises twofirst ports that are connected to the second port set 128 and one secondport that is connected to the SATA-HDD 23A.

As a result of the above constitution, the two controller circuits 101A,101B are able to access each SATA-HDD 23A and each SAS-HDD 23S. That is,the two controller circuits 101A and 101B are able to manage all of theHDDs 23 provided in the storage subsystem 1 individually. Further, theconstitution of the connection between the HDDs 23 in the expansionenclosure 1B and the BP 121 can be applied to the constitution of theconnection between the HDDs 23 in the basic enclosure 1A and the BP 17.Further, the constitution within the controller units 37A and 37B, theconstitution within the SW enclosure 3, the constitution within theexpansion enclosure 1B, and the constitution of the connection betweenthe controller units 37A and 37B and each HDD 23 are not limited to theabove example(s). Rather, several variations may be considered. Such avariation will be described by means of a fifth embodiment example(described subsequently).

FIG. 9 shows an example of the constitution of the network in a casewhere the storage subsystem 1 is connected to a communication network.

The controller circuit 101A (and/or 101B) is provided with a managementI/F 205 that functions as an interface for a management terminal 203.The management terminal 203 is connected to the management I/F 205 via acommunication network (a LAN, for example) 204. The management terminal203 is a computer machine (a personal computer or server machine, forexample) that comprises a CPU, memory, and so forth. The CPU 105 is ableto communicate with the management terminal 203 via the management I/F205. Further, the management terminal 203 may be connected to themanagement I/F 205 by means of a single cable.

A logical storage device (‘logical volume’ hereinafter) 213 is preparedon one or more HDDs 23. A group of one or more HDDs 23 that comprise thelogical volume 213 is referred to as a ‘parity group’ hereinbelow.Further, the types of the one or more HDDs that are present in oneparity group may all be the same or may be different. If the types ofthe one or more HDDs are all the same, the reliability of theconstitutional elements (HDD) of the parity group is the same. If thetypes differ, the constitution and disposition of the HDD are affordedgreater freedom.

A host device 201 is connected to the IF-FC 111 of the controllercircuit 101A (and/or 101B) via a communication network (a SAN, forexample) 202. In this case, the IF-FC 111 functions as an interfacecircuit for the host device. The CPU 105 receives a write command orread command from the host device 201 via the IF-FC 111 and executeswrite processing or read processing in response to this write command orread command. In the case of write processing, for example, the CPU 105receives data from the host device 201, writes the received data to theCache 114, and then reads this data from the Cache 114 before storingsame in the logical volume 213 (in other words, one or more HDDs 23). Inthe read processing, the CPU 105 writes the data read from the HDD 23 tothe Cache 114 and then reads the data from the Cache 114 before sendingsame to the host device 201, for example. Further, the communicationnetworks 202 and 204 may be the same communication networks.

Control information 211 is prepared in the main memory 109. The controlinformation 211 comprises data representing the relationship ofcorrespondence between the HDDs 23 and the logical volume 213. Morespecifically, for example, the control information 211 includes a volumeidentifier (a number, for example) for each logical volume 213,information relating to the parity group constituting the logical volume213 (information on each HDD 23, for example (one example is theposition, type and identifier thereof)), and the RAID level of thelogical volume 213. The control information 211 also includesinformation relating to a backup HDD (‘backup HDD’ hereinafter) 23 thatdoes not constitute the logical volume 213 (the position, type andidentifier (a WWN (World Wide Name), for example) thereof, for example).The CPU 105 is able to update the control information 211 in the mainmemory 109. For example, upon detecting removal of an HDD 23, the CPU105 specifies the position at which the HDD 23 was removed (specifiesthe position based on which eject button 85 of which HDD slot 83 hasbeen pressed, for example), and may then erase information on the HDDcorresponding with the specified position from the control information211. Further, for example, in a case where the mounting of an HDD 23 hasbeen detected, the CPU 105 may acquire information relating to the HDD23 (the CPU 105 may send a predetermined command and receive informationon the HDD 23 from the HDD 23 in response to the command, for example)and may include the acquired information in the control information 211.Further, the control information 211 may be information that is inputtedby the management terminal 203. Further, the control information 211 maybe updated by the management terminal 203. Further, the information oneach HDD 23 included in the control information 211 may include thestatus (‘active’, ‘faulty’, ‘maintainable’, ‘standby’, and‘in-preparation’, for example) of each HDD 23 detected by the CPU 105.Further, the type of each HDD 23 included in the control information 211may be automatically detected by the CPU 105. In cases where it isdetected that the HDD has been accessed directly without passing via thePS above, for example, the CPU 105 may judge that the HDD is a SAS-HDDand, when it is detected that the HDD has been accessed via the PS, theCPU 105 may judge that the HDD is a SATA-HDD. Alternatively, the CPU 105may send a predetermined command (a SCSI device discovery command, forexample) to each HDD 23 and detect the type of each HDD 23 on the basisof the information that has been sent back from each HDD 23 in responseto the command.

The CPU 105 is able to generate a GUI screen (illustrated below) on thebasis of the control information 211 and display the GUI screen on themanagement terminal 203.

FIG. 10A shows an example of a GUI screen that is displayed on themanagement terminal 203 when a fault has not occurred. The HDDinformation that is displayed on the GUI screen is information on theHDDs that exist in a enclosure (basic enclosure 1A, for example) thathas been designated by the user.

A GUI screen 301 is divided into a first subscreen 301A and a secondsubscreen 301B.

The CPU 105 displays information on the logical volume 213 on the firstsubscreen 301A. More specifically, for example, the CPU 105 displays oneor more volume graphics 308 that correspond with one or more logicalvolumes 213 and, based on the control information 211, displays anidentifier for each logical volume 213, information on the parity groupconstituting the logical volume 213, and the RAID level of the logicalvolume 213 near each volume graphic 308. Further, the CPU 105 alsodisplays information on one or more backup HDD 23 (the type andidentifier, for example) on the first subscreen 301A. Further, the CPU105 may display the type (SAS or SATA, for example) of the HDD 23corresponding with the HDD graphic 303 within the HDD graphic 303.

In addition, the CPU 105 displays information on a plurality of HDD 23that are installed in the storage subsystem 1 on the second subscreen301B on the basis of the control information 211. For example, the CPU105 displays information on all the HDDs 23 that exist in each of theenclosures 1A, 1B or on the HDDs 23 that exist in a enclosure that isspecified by the user. The second subscreen 301B shown in FIG. 10Adisplays information on the HDDs 23 that exist in the basic enclosure1A.

For example, the CPU 105 prepares locations on the second subscreen 301B(‘HDD display locations’ hereinbelow) that correspond with a pluralityof positions (positions of a plurality of HDD mounting portions 31) inthe HDD group installation drawer 19 and displays a graphic representingan HDD (‘HDD graphic’ hereinbelow) 303 at these HDD display locations.Thereupon, when the number of rows is four, for example, the CPU 105displays the number of the row closest to the front face of the basicenclosure 1A (or expansion enclosure 1B) as ‘00’ and displays the numberof the row furthest from the front face of the basic enclosure 1A (orexpansion enclosure 1B) as ‘03’. Further, the CPU 105 displaysinformation on what kind of logical volume is constituted by an HDD in aparticular position (for example, one or more HDD graphics correspondingwith one or more HDDs comprising a logical volume are framed and theidentifier of the logical volume is displayed near the frame). Further,the CPU 105 may not display HDD graphics in positions in which HDDs donot exist or may display a different form of display from the displayform (red, for example) of the HDD graphics in positions where HDDsexist. In addition, in cases where a certain HDD graphic is designatedby the user (when clicked on with a mouse, for example) the CPU 105 mayextract information on the HDD corresponding with the HDD graphic (type,identifier, status and logical volume identifier, for example) from thecontrol information 211 and then display this information. Further, theillustrated status known as ‘standby’ is a backup HDD status thatsignifies that one of the HDDs constituting the logical volume can beintegrated, for example.

FIG. 10B shows an example of a GUI screen that is displayed on themanagement terminal 203 when a fault has occurred. FIG. 10B is for acase where a fault has arisen with a certain HDD 23 that comprises alogical volume with the logical volume identifier ‘#2’.

Upon detecting that a fault has occurred in a certain HDD 23 (in a casewhere no response is received from the HDD 23 even when access isretried a predetermined number of times, for example), the CPU 105references the control information 211 to specify the identifier of thelogical volume 213 that comprises the HDD (‘faulty HDD’ hereinbelow) 23in which a fault has been detected. Further, the CPU 105 highlightsgraphic 308 of the logical volume 213 with a specified identifier ‘#2’on the first subscreen 301A (the graphic 308 is circled by a bomb mark309, for example). The CPU 105 also displays ‘redundant’ as the statusof the logical volume 213 with the identifier “#2”.

Further, the CPU 105 highlights an HDD graphic 303A at the HDD displaylocation corresponding with the position of the faulty HDD 23 on thesecond subscreen 301B. Further, the CPU 105 displays information on thefaulty HDD 23 (the type, ‘faulty’ status, and logical volume identifier,for example) so that this information is associated with the HDD graphic303A.

Thus, the CPU 105 is able to inform the user of the nature of the faultwhen a fault has occurred in the storage subsystem 1. The CPU 105 maydetect a recovery-in-progress status and display this status on thesecond subscreen 301B. For example, when the CPU 105 receives aninstruction from the management terminal 203 to include ‘standby’ statusHDDs in one of the parity groups comprising a certain logical volume,the CPU 105 includes these HDDs in one of the parity groups and mayaccordingly execute HDD integration processing, which increases thestorage capacity of the certain logical volume. Further, here, if theHDD integration processing has started, the CPU 105 may switch thestatus of the HDD to be processed from ‘standby’ to ‘in preparation’and, as shown in FIG. 10B, display the ‘in preparation’ status so thatsame is associated with an HDD GRAPHIC 303B that corresponds with theHDD to be processed. Further, if the HDD integration processing iscomplete, the CPU 105 may switch the status of the HDD to be processedfrom ‘in preparation’ to ‘active’ and display the ‘active’ status sothat same is associated with the HDD GRAPHIC 303B corresponding with theHDD to be processed.

FIG. 11 shows an example of the flow of processing that is executed upuntil a fault is recovered after a fault occurs with an HDD.

When a fault has occurred with a certain HDD 23, the fault is detectedby the CPU 105. Thereupon, the CPU 105 causes the first state displaylamps 81A and 81B (see FIG. 4A) that correspond with the faulty HDD 23to execute a display that signifies that a fault has occurred. The CPU105 also causes the second state display lamp 33 corresponding with thecolumn to which the faulty HDD 23 belongs to execute a display thatsignifies that a fault has occurred in that column (step S100) The CPU105 displays a GUI screen 301, on which information on the HDD 23 (theposition, status, and the like, for example) in which the fault hasoccurred is placed, on the management terminal 203 on the basis of thecontrol information 211 (S200) A user 401 of the management terminal 203views the GUI screen 301 displayed on the management terminal 203,examines the strategy regarding which settings are to be made for thestorage subsystem 1, and then uses the management terminal 203 to makesettings for the storage subsystem 1 based on the examination results(S300, S301). The CPU 105 of the storage subsystem 1 analyses thecontent of the settings and then executes processing based on theresults of the analysis (S400).

A specific example of S301 and S400 will be provided below.

In S301, the management terminal 203 releases the lock on the faulty HDD23 in accordance with an operation by the user 401 and then inputs thesettings to include the backup HDD selected by the user (‘selectedbackup HDD’ hereinbelow) in the parity group that includes the faultyHDD 23 to the storage subsystem 1.

The CPU 105 of the storage subsystem 1 then releases the lock on thefaulty HDD 23 by controlling the lock mechanism 87 of the faulty HDD 23in accordance with the settings thus inputted (S401). Thereupon, the CPU105 may change the status of the faulty HDD 23 from ‘faulty’ to‘maintainable’ and display the changed status on the management terminal203 so that the changed status is associated with the HDD graphic of thefaulty HDD 23. Further, the CPU 105 may also release the lock on all ofthe HDD 23 that constitute the parity group (hereinafter ‘faulty group’)that includes the faulty HDD 23. This serves to enable HDD replacementin parity group units. Further, the CPU 105 may not access the HDD 23whose lock has been released (for example, in a case where a writecommand or read command for the logical volume that the HDD 23 compriseshas been received, notification to the effect that access is nowprohibited may be sent back to the host device). Further, the CPU 105may issue notification that the lock control button 35 correspondingwith the column of the faulty HDD 23 has been pressed (the display ofthe second state display lamp 33 is controlled to provide notificationto that effect, for example) and the lock of the faulty HDD 23 may bereleased after it is detected that the lock control button 35 has beenpressed by way of response.

Further, the CPU 105 turns OFF the power supply of the faulty HDD 23 inaccordance with the inputted settings (S402). The CPU 105 may then turnOFF the power supply of all the HDD 23 constituting the faulty group. Asthe method for turning OFF the power supply, a method in which, in acase where the HDD group mounting substrate 21 is provided with a powersupply circuit 404 that supplies electrical power to the HDD 23, the CPU105 turns OFF the power supply of the HDD 23 by sending a power supplyturn-OFF command to the power supply circuit 404, may be considered.

Further, the CPU 105 may cause the first state display lamps 81A and 81Bcorresponding with the faulty HDD 23 to execute a display to the effectthat the lock on the faulty HDD 23 has been released (S403).

The CPU 105 also executes processing to include the selected backup HDD23 in the parity group in place of the faulty HDD 23 (S404). Forexample, the CPU 105 updates the control information 211 to informationthat includes content indicating the fact that the selected backup HDD23 is included in the faulty group in place of the faulty HDD 23.

The first embodiment example was described above. Further, in the firstembodiment example, instead of withdrawing or pushing in the HDD groupinstallation drawer 19 and mounting or removing the HDD 23, theconstitution is such that the upper faces of the enclosures 1A and 1Bopen and close such that mounting or removal of the HDD 23 may beperformed by opening these upper faces. The upper faces of theenclosures 1A and 1B may be opened and closed by turning the enclosures1A, 1B with a certain edge serving as the axis or may be opened andclosed by sliding along the upper faces in the directions of twodimensions, for example. According to the above first embodiment examplehereinabove, a plurality of HDDs 23 may be arranged upright in the depthdirection of the enclosures 1A and 1B. As a result, HDDs 23 can beprovided at a high density within a fixed space. As a result, a higherperformance and capacity for the storage subsystem 1 are also possible.

Furthermore, according to the above first embodiment example, aplurality of HDDs 23 is arranged at equal intervals in the row directionthat is orthogonal to the direction in which the cooling air streamflows. As a result, because all the widths of the intercolumn paths 91are then the same, the volume, velocity, and so forth, of the coolingair stream passing through each intercolumn path 91 can be made uniform.

Further, according to the above first embodiment example, the lockcontrol button 35 is provided for each column constituted by two or moreHDDs and, unless the lock control button 35 corresponding with thedesired column is pressed, the HDDs 23 belonging to that column cannotbe removed. As a result, it is possible to prevent erroneous removal ofHDDs that are present in the rows adjacent to an HDD that is to beremoved and therefore maintenance work on the storage subsystem 1 can beperformed accurately.

Further, several variations may be considered based on a variety offacts in the first embodiment example above. Embodiment examples forwhich a variety of variations has been adopted will be describedhereinbelow as other embodiment examples. Further, in the followingdescription, descriptions of points that are also common to the firstembodiment example are omitted or simplified. Points of difference fromthe first embodiment example will mainly be described.

Second Embodiment Example

In the second embodiment, the method of withdrawing the HDD groupinstallation drawer 19 differs from that of the first embodimentexample.

Withdrawal methods include, for example, a method (referred to as the‘integrated withdrawal method’ hereinafter) in which the HDD groupinstallation drawer 19 is withdrawn integrally with the rear-side parts(the back plane 17 and the parts that exist further in the depthdirection than the back plane 17) and a method (referred to as the‘separate withdrawal method’ hereinafter) in which the HDD groupinstallation drawer 19 is withdrawn separately from the back plane 17.Variations on each withdrawal method will be described below.

(A) Integrated Withdrawal Method

FIG. 12A shows a first variation on the integrated withdrawal method.

According to the first variation, a cable (hereinafter ‘external cable’)77, which is connected to the rear-side connector 43 of the power supplyunit 39, controller units 37A, 37B, and so forth, is drawn toward thefront side and introduced to the basic enclosure 1A in accordance withthe sliding action of the HDD group installation drawer 19 and, when theHDD group installation drawer 19 is pushed toward the rear side, thecable 77 is made to exit the basic enclosure 1A.

According to the first variation, the rear face of the basic enclosure1A is open. It is therefore, easy to exchange the power supply unit 39and controller units 37A, 37B, and so forth.

FIG. 12B shows a second variation on the integrated withdrawal methodfrom which an illustration of the slide mechanism 27 has been omitted.

According to this second variation, a boundary substrate 79 is providednear the rear face of the basic enclosure 1A. The boundary substrate 79is a printed substrate, for example, and the space near the rear face ofthe basic enclosure 1A is divided into the front side and rear side ofthe basic enclosure 1A. The boundary substrate 79 comprises, on the rearface thereof, a connector 81 for connecting the external cable 77 andcomprises, on the front side, a connector 80 that is connected to therear-side connector 43 of the power supply unit or the like via aninternal cable 78. The position of the boundary substrate 79 is fixedand the boundary substrate 79 does not move in accordance with theinsertion and withdrawal of the HDD group installation drawer 19.

Further, according to the second variation, the boundary substrate 79,power supply unit 39, and controller units 37A, 37B, and so forth areconstituted as a single module, meaning that the power supply unit 39and controller units 37A, 37B, and so forth may be exchanged for anotherpower supply unit 39, and controller units 37A, 37B, and so forth byexchanging the module.

FIG. 12C shows a third variation on the integrated withdrawal methodfrom which an illustration of the slide mechanism 27 has been omitted.

The third variation is a modified example of the second variation above.That is, a new connector 501 is provided on the rear face of the backplane 17 and the front-face connector 80 of the boundary substrate 79 isconnected to the connector 501 via the internal cable 78. The internalcable 78 is stored in the space between the controller unit 37B and thebottom of the basic enclosure 1A. The internal cable 78 is aflexible-film-like cable, for example.

According to the third variation, the number of parts can be reduced.For example, the number of internal cables 78, the number of front-sideconnectors 80 of the boundary substrate 79, and the number of rear-sideconnectors 43 of the respective units 39, 37A and 37B can be reduced.Further, it is understood that the constitution of the printed wiring ofthe back plane 17 in the third variation differs from that of the firstembodiment example.

(B) Separate Withdrawal Method

FIG. 13A provides an outline of one variation on the separate withdrawalmethod and FIG. 13B serves to illustrate the variation in detail.

According to the variation on the separate withdrawal method shown inFIGS. 13A and 13B, the HDD group installation drawer 19 is constitutedby n subdrawers 19S. The value of n is an integer of two or more and avalue less than the number of columns of the HDD 23. Further, in thissecond embodiment example, n is the same number as the number of columnsof the HDD 23.

HDDs 23 that constitute one or more columns (one column in thisembodiment example) are mounted in one subdrawer 19S. Each subdrawer 19Smay have the constitution of the HDD group installation drawer 19. Forexample, each subdrawer 19S may comprise, at the bottom thereof, an HDDgroup installation sub-substrate for mounting the HDDs that belong tothe column corresponding with the subdrawer 19S.

Each subdrawer 19S is withdrawn separately from the back plane 17 asshown in FIGS. 13A and 13B. That is, although there is no specialillustration, each subdrawer 19S is provided with a slide mechanism forsliding the subdrawer 19S toward the front side and toward the rearside. As per the first embodiment example, this slide mechanism may beconstituted by a rail and guide rollers.

The connector 47 of each subdrawer 19S is connected electrically to theHDD 23 that is mounted in the subdrawer 19S. Further, the connector 47of each subdrawer 19S is connected to the front-side connector 48 of theback plane 17 via a cable 508. The cable 508 is a flexible-film-likecable, for example. As a result, in a state where the subdrawer 19S iscompletely housed within the basic enclosure 1A, the cable 508 is housedin a space between the subdrawer 19S and the bottom of the basicenclosure 1A (a space that has the height of the rail 25, for example.Further, in this variation, an extendable rail may be provided insteadof providing the cable 508. In such a case, when the subdrawer 19 iswithdrawn, the rail extends (that is, grows longer) toward the frontside and contracts (that is, grows shorter) toward the rear side whenthe subdrawer 19 is pushed in.

Third Embodiment Example

In the third embodiment example, the removal method for the HDD 23differs from that of the first embodiment example.

FIG. 14A shows a first variation on the removal method for the HDD 23.

In the first variation, an elastic body (a spring, for example) 511whose height runs vertically is provided between the HDD mountingportion 31 and HDD group mounting substrate 21. In this first variation,the mounting and removal of the HDD 23 is executed according to thefollowing processing flow.

That is, the HDD 23 is pressed vertically downward for insertion intothe HDD slot 83 and, when the HDD 23 no longer extends after the elasticbody 511 has collapsed according to a certain measure, the elastic body511 returns to and stops in a position below the original height thereofsuch that the upper face 23U of the HDD 23 is then located in the sameposition as the face of the HDD slot 83 or in a position below same. TheHDD 23 thus enters a mounted state.

Thereafter, when the upper face 23U of the HDD 23 is pressed verticallydownward and the elastic body 511 is collapsed according to a certainmeasure, the elastic body 511 returns to the original height and theupper face 23U of the HDD 23 is then located in a plane above the faceof the HDD slot 83. The HDD 23 thus enters a removable state.

FIG. 14B shows a second variation on the removal method for the HDD 23.

According to the second variation, a handle 512 is provided on the upperface of the HDD 23 (or of the canister housing the HDD 23). The userholds the handle 512 and is able to remove the HDD 23 by drawing thehandle 512 upward in a vertical direction.

Further, the handle 512 may be mounted detachably on the HDD 23 (or thecanister housing the HDD 23). Further, the shape of the handle 512 maybe any shape as long as same can be gripped by hand. Further, in placeof the handle 512, a tool for pulling out the HDD 23 may be provided byusing any means (through engagement or hooking, for example) may beprovided.

Fourth Embodiment Example

In a fourth embodiment example, the cooling design of the HDD 23 differsfrom that of the first embodiment example. That is, according to thefirst embodiment example, the volume (or velocity) of the air streamflowing through the intercolumn paths 91 is substantially uniform overthe interval from the inlet to the outlet thereof but is not uniform inthe fourth embodiment example. More specifically, for example, accordingto the fourth embodiment example, the flow path of the air streamnarrows from the front side toward the rear side (that is, as progressis made movement in the depth direction). As a result, the air streamvelocity increases in moving toward the rear side and hence the coolingefficiency of the HDDs 23 that exist on the rear side can be improved.

FIG. 15A shows a first variation on the cooling design for increasingthe velocity of the cooling air stream on the rear side.

According to the first variation, a dividing member 564 that is long inthe depth direction is disposed in the intercolumn path 91. The dividingmember 564 splits the intercolumn path 91 into two subpaths 91S, 91Sfrom a point that is a predetermined distance apart from the opening ofthe intercolumn path 91 (close to the second row, for example) and thewidth of the subpath 91S narrows in the depth direction. The dividingmember 564 has a narrow width at the leading end (on the side oppositethe depth direction) and widens at the trailing end (on the depthdirection side), for example, and is a member with the same height asthe height of the intercolumn path 91. Because this dividing member 564is disposed with the leading edge facing toward the front face and therear edge facing toward the rear face, the intercolumn path 91 isdivided into two subpaths 91S, 91S, the width (that is, the interval inthe row direction) of each subpath 91S growing narrower in the depthdirection. As a result, the cooling air stream flowing through theintercolumn path 91 increases in velocity as same progresses in thedepth direction, as indicated by the reference numerals 561 to 563.

Further, various variations are possible for the shape of the dividingmember 564. The shape of the dividing member 564 may also be altered.For example, the dividing member 564 may be a plate in the form of aletter V (a metal plate, for example) such that the width between theleading edge and trailing edge can be adjusted by controlling the angleof the pointed end.

FIG. 15B shows a second variation on the cooling design for increasingthe velocity of the cooling air stream on the rear side.

In the case of the second variation, the column formed by two or moreHDDs 23 is inclined in the depth direction so that the width betweenadjacent columns is narrower on the rear side than on the front side.Further, an adjustment member 565 for narrowing, in the depth direction,the width of the path of the cooling air stream flowing through the areaadjacent to the first column (on the side where an adjacent column isnot present), is provided in this adjacent area.

Further, in this second variation, the HDD group installation drawer 19may have a constitution for adjusting the inclination of each column.For example, the HDD group mounting substrate 21 may be divided into aplurality of long paper-strip-like sub-substrates (sub-substrates thatcan comprise a column) oriented in the depth direction, and theinclination of each column may be adjusted by changing the inclinationwith respect to the depth direction of the sub-substrates.

Fifth Embodiment Example

In the fifth embodiment, at least one of the constitution within thecontroller units 37A and 37B, the constitution within the SW enclosure3, the constitution within the expansion enclosure 1B and theconstitution of the connection between the controller units 37A and 37Band each HDD 23 is different from that of the first embodiment example.

FIG. 16 shows one variation on the constitution within the expansionenclosure 1B.

According to this variation, the SAS-HDD 23S and SATA-HDD 23A are notmixed within the expansion enclosure 1B. Instead, only SAS-HDDs 23S arepresent. That is, only SAS-HDDs 23S are connected to the BP 121. TheSAS-HDDs 23S have two ports as mentioned earlier and therefore can beconnected directly to the BP 121 without the interposition of the PS123.

So too with this variation, the two controller circuits 101A and 101Bare able to manage all of the HDDs 23 provided in the storage subsystem1 individually.

FIG. 17 shows another variation on the constitution within the expansionenclosure 1B.

According to this variation, the SAS-HDD 23S and SATA-HDD 23A are notmixed within the expansion enclosure 1B. Instead, only SATA-HDDs 23A arepresent. That is, only SATA-HDDs 23A are connected to the BP 121. TheSATA-HDDs 23A are equipped with only one port as mentioned earlier andare therefore connected to the BP 121 via the PS 123.

So too with this variation, the two controller circuits 101A and 101Bare able to manage all of the HDDs 23 provided in the storage subsystem1 individually.

FIG. 18 shows yet another variation on the constitution within theexpansion enclosure 1B and one variation on the constitution of theconnection between the controller units 37A, 37B and each HDD 23. FIG.19 shows the constitution of the HDD group installation drawer in theexpansion enclosure 1B in detail.

According to FIGS. 18 and 19, the HDD group installation drawer 19 inthe expansion enclosure 1B comprises a plurality of subdrawers 19S. Thatis, the plurality of HDD 23 in the expansion enclosure 1B is logicallydivided into n columns (n is an integer of one or more).

The arrangement of the HDD 23 may be the same for the whole plurality ofsubdrawers 19S or may be different. For example, as indicated by thereference number 19SA in FIG. 19, all of the two or more HDDs 23 mountedin at least one subdrawer 19S of the plurality of subdrawers 19S may bea SAS-HDD 23S. Further, as indicated by the reference number 19SB, allof the two or more HDDs 23 mounted in at least one of the plurality ofsubdrawers 19S may be a SATA-HDD 23A. Further, two or more of the HDD 23that are mounted in at least one subdrawer 19S of the plurality ofsubdrawers 19S may be a combination of SAS-HDDs 23S and SATA-HDDs 23A,for example. In this case, the SATA-HDD 23A and SAS-HDD 23S may bealternated moving in the direction from the front side of the expansionenclosure 1B toward the rear side in at least one subdrawer 19SC of theplurality of subdrawers 19S. Further, at least one subdrawer 19SD of theplurality of subdrawers 19S may have a concentration of SATA-HDDs 23A onthe front side thereof and a concentration of SAS-HDDs 23S on the rearside thereof.

According to FIG. 18, the controller circuits 101A and 101B areconnected to the expansion enclosure 1B without the interposition of theSW enclosure 3. Further, the first controller circuit 101A is connectedto the HDDs 23 that exist on the rear side of each subdrawer 19S but isnot connected to the HDDs 23 that exist on the front side. The secondcontroller circuit 101B is connected to the HDDs 23 that exist on thefront side of each subdrawer 19S but is not connected to the rear-sideHDDs 23 to which the first controller circuit 101A is connected.

Several embodiments of the present invention were described hereinabovebut the present invention is not limited to or by the above embodiments.A person skilled in the art is able to add to, take from or modify theconstitution within the scope of the present invention. For example,because the illustrated flowchart is merely a flowchart to show clearlythe processing flow, a person skilled in the art is able to switch,cancel or modify the steps easily so that an understanding andimplementation of the invention are not impaired.

For example, among the connecting lines between the back plane 17 andHDD 23 or the connecting lines between the back plane 17 and each of theunits 19, 37A and 37B, the power supply line may be constituted bywiring on the printed substrate and the signal line (the data transferline, for example) may be constituted by a cable.

Moreover, a combination of columns that are constituted by SATA-HDD 23Aand columns that are constituted by SAS-HDD 23S in the enclosures 1A and1B are acceptable. In this case, the width of at least one intercolumnpath 91 of the two intercolumn paths 91 adjacent to the columnconstituted by the SAS-HDDs 23S is greater than the width of at leastone intercolumn path 91 among the two intercolumn paths 91 adjacent tothe column constituted by the SATA-HDD 23A. This is because the SAS-HDD23S reaches a high temperature more readily than the SATA-HDD 23A andtherefore the volume of the air stream flowing adjacent to the column ofSAS-HDDs 23S is greater than the volume of the air stream flowingadjacent to the column of SATA-HDDs 23A. FIG. 20A shows a specificexample. In FIG. 20, columns constituted by SATA-HDDs 23A and columnsconstituted by SAS-HDDs 23S are arranged alternately.

Further, for example, control of the power supply of the plurality ofHDDs 23 (to turn the power supply ON and OFF, for example) in each ofthe enclosures 1A and 1B may be performed for each HDD 23 or may beperformed in n-column units (may be executed in units of the subdrawers19S, for example) or in x-row units (x is an integer of one or more),for example.

Moreover, for example, the types of HDDs 23 are not limited to at leastone type of SAS and SATA. There may instead be different types (FiberChannel, for example).

1. A storage subsystem that is connected to an external device,comprising: a plurality of enclosures each of which has a drawerslideable in a depth direction of a horizontal plane therein andthereout, each drawer including a plurality of slots for insertingupright therein a storage device; and a control device that is connectedto the external device, controls communications between the plurality ofstorage devices and the external device, and sends information to theexternal device to display a corresponding relationship between logicalvolumes and physical positions of the storage devices in each enclosure,each logical volume being a logical storage device formed on one or moreof the storage devices, wherein each of the storage devices is insertedor removed after the respective drawer is pulled out from the respectiveenclosure, and wherein the plurality of storage devices includes alow-heat storage device that emits heat by consuming first electricalpower and a high-heat storage device that emits heat that is of a highertemperature than the heat of the low-heat storage device by consumingsecond electrical power, the storage subsystem further comprises: acooling portion that causes a gas for cooling the storage devicesarranged on the storage device arrangement portion to flow to thestorage device arrangement portion, and the storage device arrangementportion is constituted such that the low-heat storage device is disposedupstream in the direction in which the gas flows and the high-heatstorage device is disposed downstream in the direction in which the gasflows.
 2. The storage subsystem according to claim 1, furthercomprising: a slide mechanism that slides the drawer inside and outsidethe respective enclosure.
 3. The storage subsystem according to claim 2,wherein the drawer comprises: a first sub-arrangement portion forarranging two or more first storage devices among the plurality ofstorage devices; and a second sub-arrangement portion for arranging twoor more second storage devices among the plurality of storage devices,and the slide mechanism slides the first sub-arrangement portion and thesecond sub-arrangement portion separately.
 4. The storage subsystemaccording to claim 1, further comprising: a cooling portion that causesa gas for cooling the storage devices to flow to the drawer, wherein gasflows are formed in the depth direction as separated by the M storagedevice columns at equal intervals.
 5. The storage subsystem according toclaim 1, further comprising: a cooling portion that causes a gas forcooling the storage devices to flow to the drawer; and a dummy storagedevice disposed on a slot of the drawer so that the flow of gas is notdisturbed when a number of storage devices is smaller than the maximumnumber of storage devices that can be arranged in the drawer.
 6. Thestorage subsystem according to claim 1, further comprising: a coolingportion that causes a gas for cooling the storage devices to flow to thedrawer, wherein a plurality of storage devices are arranged in a matrixwith M columns of storage devices in a width direction of the horizontalplane and N rows of storage devices in the depth direction, and whereingas flows are formed to flow through a plurality of flow paths among theM storage device columns, and the width of at least one of the flowpaths is narrower downstream than upstream in the depth direction. 7.The storage subsystem according to claim 1, wherein a plurality ofstorage devices are arranged in a matrix with M columns of storagedevices in a width direction of the horizontal plane and N rows ofstorage devices in the depth direction, the drawer includes Msub-drawers each corresponding to one of the M storage device columns,and one of the sub-drawers is selected by a user to be slide out of arespective enclosure so as to remove a damaged storage device thatbelongs to the selected storage device column.
 8. The storage subsystemaccording to claim 1, wherein the plurality of storage devices includesa low-heat storage device that emits heat by consuming first electricalpower and a high-heat storage device that emits heat that is of a highertemperature than the heat of the low-heat storage device by consumingsecond electrical power, the storage subsystem further comprises: acooling portion that causes a gas for cooling the storage devicesarranged on the storage device arrangement portion to flow to thestorage device arrangement portion, and the storage device arrangementportion is constituted such that the low-heat storage device is disposedupstream in the direction in which the gas flows and the high-heatstorage device is disposed downstream in the direction in which the gasflows.
 9. A storage subsystem that is connected to an external device,comprising: a plurality of enclosures each of which has a drawerslideable in a depth direction of a horizontal plane therein andthereout, each drawer including a plurality of slots for insertingupright therein a storage device such that a plurality of storagedevices are arranged in a matrix with M columns of storage devices in awidth direction of the horizontal plane and N rows of storage devices inthe depth direction; a slide mechanism that slides the drawer inside andoutside the respective enclosure; a cooling portion that causes a gasfor cooling the storage devices to flow to the drawer; and a controldevice that is connected to the external device, controls communicationsbetween the plurality of storage devices and the external device, andsends information to the external device to display a correspondingrelationship between logical volumes and physical positions of thestorage devices in each enclosure, each logical volume being a logicalstorage device formed on one or more of the storage devices, whereineach of the storage devices is inserted or removed after the respectivedrawer is pulled out from the respective enclosure, gas flows are formedin the depth direction as separated by the M storage device columns atequal intervals, and the drawer includes M sub-drawers eachcorresponding to one of the M storage device columns, and one of thesub-drawers is selected by a user as detected to be slide out of arespective enclosure so as to remove a damaged storage device thatbelongs to the selected storage device column, wherein the plurality ofstorage devices includes a low-heat storage device that emits heat byconsuming first electrical power and a high-heat storage device thatemits heat that is of a higher temperature than the heat of the low-heatstorage device by consuming second electrical power, the storagesubsystem further comprises: a cooling portion that causes a gas forcooling the storage devices arranged on the storage device arrangementportion to flow to the storage device arrangement portion, and thestorage device arrangement portion is constituted such that the low-heatstorage device is disposed upstream in the direction in which the gasflows and the high-heat storage device is disposed downstream in thedirection in which the gas flows.
 10. A storage subsystem that isconnected to an external device, comprising: a plurality of enclosureseach of which has a drawer slideable in a depth direction of ahorizontal plane therein and thereout, each drawer including a pluralityof slots for inserting upright therein a storage device; a controldevice that is connected to the external device, controls communicationsbetween the plurality of storage devices and the external device, andsends information to the external device to display a correspondingrelationship between logical volumes and physical positions of thestorage devices in each enclosure, each logical volume being a logicalstorage device formed on one or more of the storage devices, and whereineach of the storage devices is inserted or removed after the respectivedrawer is pulled out from the respective enclosure; and a coolingportion that causes a gas for cooling the storage devices to flow to thedrawer, wherein gas flows are formed in the depth direction as separatedby a plurality of storage device columns at equal intervals.
 11. Thestorage subsystem according to claim 10, further comprising: a slidemechanism that slides the drawer inside and outside the respectiveenclosure.
 12. The storage subsystem according to claim 11, wherein thedrawer comprises: a first sub-arrangement portion for arranging two ormore first storage devices among the plurality of storage devices; and asecond sub-arrangement portion for arranging two or more second storagedevices among the plurality of storage devices, and the slide mechanismslides the first sub-arrangement portion and the second sub-arrangementportion separately.
 13. The storage subsystem according to claim 10,further comprising: a dummy storage device disposed on a slot of thedrawer so that the flow of gas is not disturbed when a number of storagedevices is smaller than the maximum number of storage devices that canbe arranged in the drawer.
 14. The storage subsystem according to claim10, wherein a plurality of storage devices are arranged in a matrix withM columns of storage devices in a width direction of the horizontalplane and N rows of storage devices in the depth direction, and gasflows are formed to flow through a plurality of flow paths among the Mstorage device columns, and the width of at least one of the flow pathsis narrower downstream than upstream in the depth direction.
 15. Thestorage subsystem according to claim 10, wherein a plurality of storagedevices are arranged in a matrix with M columns of storage devices in awidth direction of the horizontal plane and N rows of storage devices inthe depth direction, the drawer includes M sub-drawers eachcorresponding to one of the M storage device columns, and one of thesub-drawers is selected by a user as detected to be slide out of arespective enclosure so as to remove a damaged storage device thatbelongs to the selected storage device column.
 16. A storage subsystemthat is connected to an external device, comprising: a plurality ofenclosures each of which has a drawer slideable in a depth direction ofa horizontal plane therein and thereout, each drawer including aplurality of slots for inserting upright therein a storage device suchthat a plurality of storage devices are arranged in a matrix with Mcolumns of storage devices in a width direction of the horizontal planeand N rows of storage devices in the depth direction; a slide mechanismthat slides the drawer inside and outside the respective enclosure; acooling portion that causes a gas for cooling the storage devices toflow to the drawer; and a control device that is connected to theexternal device, controls communications between the plurality ofstorage devices and the external device, and sends information to theexternal device to display a corresponding relationship between logicalvolumes and physical positions of the storage devices in each enclosure,each logical volume being a logical storage device formed on one or moreof the storage devices, wherein each of the storage devices is insertedor removed after the respective drawer is pulled out from the respectiveenclosure, gas flows are formed in the depth direction as separated bythe M storage device columns at equal intervals, and the drawer includesM sub-drawers each corresponding to one of the M storage device columns,and one of the sub-drawers is selected by a user as detected to be slideout of a respective enclosure so as to remove a damaged storage devicethat belongs to the selected storage device column.
 17. A storagesubsystem that is connected to an external device, comprising: aplurality of enclosures each of which has a drawer slideable in a depthdirection of a horizontal plane therein and thereout, each drawerincluding a plurality of slots for inserting upright therein a storagedevice such that a plurality of storage devices are arranged in a matrixwith M columns of storage devices in a width direction of the horizontalplane and N rows of storage devices in the depth direction; a controldevice that is connected to the external device, controls communicationsbetween the plurality of storage devices and the external device, andsends information to the external device to display a correspondingrelationship between logical volumes and physical positions of thestorage devices in each enclosure, each logical volume being a logicalstorage device formed on one or more of the storage devices, whereineach of the storage devices is inserted or removed after the respectivedrawer is pulled out from the respective enclosure, and when one of thestorage devices is damaged, the control device sends to the externaldevice information of a corresponding relationship between a physicalposition of the damaged storage device in a respective enclosure and alogical volume to display the corresponding relationship; and a coolingportion that causes a gas for cooling the storage devices to flow to thedrawer, wherein gas flows are formed in the depth direction as separatedby the M storage device columns at equal intervals.
 18. The storagesubsystem according to claim 17, further comprising: a slide mechanismthat slides the drawer inside and outside the respective enclosure. 19.The storage subsystem according to claim 18, wherein the drawercomprises: a first sub-arrangement portion for arranging two or morefirst storage devices among the plurality of storage devices; and asecond sub-arrangement portion for arranging two or more second storagedevices among the plurality of storage devices, and the slide mechanismslides the first sub-arrangement portion and the second sub-arrangementportion separately.
 20. The storage subsystem according to claim 17,further comprising: a dummy storage device disposed on a slot of thedrawer so that the flow of gas is not disturbed when a number of storagedevices is smaller than the maximum number of storage devices that canbe arranged in the drawer.
 21. The storage subsystem according to claim17, wherein gas flows are formed to flow through a plurality of flowpaths among the M storage device columns, and the width of at least oneof the flow paths is narrower downstream than upstream in the depthdirection.
 22. The storage subsystem according to claim 17, wherein thedrawer includes M sub-drawers each corresponding to one of the M storagedevice columns, and one of the sub-drawers is selected by a user asdetected to be slide out of a respective enclosure so as to remove adamaged storage device that belongs to the selected storage devicecolumn.
 23. A storage subsystem that is connected to an external device,comprising: a plurality of enclosures each of which has a drawerslideable in a depth direction of a horizontal plane therein andthereout, each drawer including a plurality of slots for insertingupright therein a storage device such that a plurality of storagedevices are arranged in a matrix with M columns of storage devices in awidth direction of the horizontal plane and N rows of storage devices inthe depth direction; a slide mechanism that slides the drawer inside andoutside the respective enclosure; a cooling portion that causes a gasfor cooling the storage devices to flow to the drawer; and a controldevice that is connected to the external device, controls communicationsbetween the plurality of storage devices and the external device, andsends information to the external device to display a correspondingrelationship between logical volumes and physical positions of thestorage devices in each enclosure, each logical volume being a logicalstorage device formed on one or more of the storage devices, whereineach of the storage devices is inserted or removed after the respectivedrawer is pulled out from the respective enclosure, when one of thestorage devices is damaged, the control device sends to the externaldevice information of a corresponding relationship between a physicalposition of the damaged storage device in a respective enclosure and alogical volume to display the corresponding relationship, gas flows areformed in the depth direction as separated by the M storage devicecolumns at equal intervals, and the drawer includes M sub-drawers eachcorresponding to one of the M storage device columns, and one of thesub-drawers is selected by a user as detected to be slide out of arespective enclosure so as to remove a damaged storage device thatbelongs to the selected storage device column.
 24. A storage subsystemthat is connected to an external device, comprising: a storage devicearrangement portion on which a plurality of storage devices is arranged;and a control device that controls communications between the pluralityof storage devices arranged on the storage device arrangement portionand the external device, wherein the storage device arrangement portionis constituted such that the plurality of storage devices is arrangedupright in the directions of two dimensions.
 25. The storage subsystemaccording to claim 24, further comprising: a enclosure for housing thestorage device arrangement portion; and an arrangement portiondisplacement mechanism that displaces the storage device arrangementportion inside and outside the enclosure.
 26. The storage subsystemaccording to claim 25, wherein the storage device arrangement portioncomprises: a first sub-arrangement portion for arranging two or morefirst storage devices among the plurality of storage devices; and asecond sub-arrangement portion for arranging two or more second storagedevices among the plurality of storage devices, and the arrangementportion displacement mechanism displaces the first sub-arrangementportion and the second sub-arrangement portion separately.
 27. Thestorage subsystem according to claim 24, wherein the storage devicearrangement portion comprises a plurality of storage device slotscorresponding with a plurality of storage devices respectively and isconstituted to arrange a plurality of storage devices, each of which isinserted via the plurality of storage device slots; and each of theplurality of storage device slots is constituted to receive a storagedevice in an upright state vertically from above.
 28. The storagesubsystem according to claim 24, further comprising: a cooling portionthat causes a gas for cooling the storage devices arranged on thestorage device arrangement portion to flow to the storage devicearrangement portion, wherein the storage device arrangement portion isconstituted such that a plurality of storage device columns consistingof two or more storage devices that follow the direction in which thegas flows are formed and the plurality of storage device columns are atequal intervals.
 29. The storage subsystem according to claim 24,wherein the plurality of storage devices includes a low-heat storagedevice that emits heat by consuming first electrical power and ahigh-heat storage device that emits heat that is of a higher temperaturethan the heat of the low-heat storage device by consuming secondelectrical power, the storage subsystem further comprises: a coolingportion that causes a gas for cooling the storage devices arranged onthe storage device arrangement portion to flow to the storage devicearrangement portion, and the storage device arrangement portion isconstituted such that the low-heat storage device is disposed upstreamin the direction in which the gas flows and the high-heat storage deviceis disposed downstream in the direction in which the gas flows.
 30. Thestorage subsystem according to claim 24, further comprising: a coolingportion that causes a gas for cooling the storage devices arranged onthe storage device arrangement portion to flow to the storage devicearrangement portion; and a storage device dummy that is disposed on thestorage device arrangement portion so that the flow of gas is notdisturbed when the maximum number of storage devices that can bearranged is not arranged on the storage device arrangement portion. 31.The storage subsystem according to claim 24, further comprising: acooling portion that causes a gas for cooling the storage devicesarranged on the storage device arrangement portion to flow to thestorage device arrangement portion, wherein the storage devicearrangement portion is constituted such that a plurality of storagedevice columns consisting of two or more storage devices that follow thedirection in which the gas flows are formed and the width of at leastone storage device column among the plurality of storage device columnsis narrower downstream than upstream in the direction in which the gasflows.
 32. The storage subsystem according to claim 24, wherein thestorage device arrangement portion is constituted such that a pluralityof storage device columns consisting of two or more storage devices areformed, and the storage subsystem further comprises: a plurality ofoperating portions corresponding with the plurality of storage devicecolumns respectively, wherein the operation of an operating portion thatis selected by a user from among the plurality of operating portions isdetected and the user is allowed to remove a storage device that belongsto the storage device column corresponding with the selected operatingportion.
 33. The storage subsystem according to claim 32, furthercomprising: a enclosure for housing the storage device arrangementportion; and an arrangement portion displacement mechanism thatdisplaces the storage device arrangement portion inside and outside theenclosure and in the directions of the two dimensions.
 34. The storagesubsystem according to claim 24, wherein the storage device arrangementportion comprises a plurality of arrangement positions correspondingwith the plurality of storage devices respectively, and the controldevice comprises: a storage region that stores control informationindicating where in the plurality of arrangement positions which typesof storage devices are arranged and indicating the respective states ofeach of the storage devices; and a control portion that displays a GUIscreen, wherein the control portion prepares a plurality of displaypositions on the GUI screen corresponding with the plurality ofarrangement positions respectively, displays a graphic representing anarranged storage device in each of the plurality of display positions,and displays at least one of the type and state of the storage devicecorresponding with the graphic on the GUI screen so that the type and/orstate is associated with the graphic.
 35. A storage subsystem that isconnected to an external device and that possesses depth, comprising: astorage device arrangement portion on which a plurality of storagedevices is arranged upright in the directions of two dimensions thatinclude the depth direction of the storage subsystem; a control devicethat controls communications between the plurality of storage devicesarranged on the storage device arrangement portion and the externaldevice; a cooling portion that causes a gas for cooling the storagedevices arranged on the storage device arrangement portion to flow tothe storage device arrangement portion; a enclosure for housing thestorage device arrangement portion, the control device and the coolingportion; and an arrangement portion displacement mechanism thatdisplaces the storage device arrangement portion inside and outside theenclosure and in the directions of the two dimensions, wherein thestorage device arrangement portion is constituted such that a pluralityof storage device columns consisting of two or more storage devices thatfollow the direction in which the gas flows are formed so that theplurality of storage device columns are at equal intervals or so thatthe width of at least one storage device column among the plurality ofstorage device columns is narrower downstream than upstream in thedirection in which the gas flows; and the storage subsystem furthercomprises: a plurality of operating portions corresponding with theplurality of storage device columns respectively, wherein the operationof an operating portion that is selected by a user from among theplurality of operating portions is detected and the user is allowed toremove a storage device that belongs to the storage device columncorresponding with the selected operating portion.